The effect of increasing the strength of a rubber or the hysteresis loss at the time of repeated deformation by blending a filler (filler material) such as carbon black or silica into a rubber (reinforcing effect) is well known. In a rubber composition for a tire containing a filler, an increase in the strength of the rubber material for the tire leads to an increase in durability or wear resistance. In general, increasing the hysteresis loss makes it possible to improve the wet grip performance and to improve the safety of the vehicle, but at the same time, the roll resistance is increased and the fuel consumption performance is reduced. In this way, tires have contradictory performance factors such as wet grip performance and fuel consumption performance. However, there has been a demand for improvements in the fuel consumption performance of tires due to an increased awareness of energy conservation in recent years. That is, there is a demand to improve fuel consumption performance without sacrificing the wet grip performance of tires.
It has been proposed to blend a triphenylborane-triphenylphosphine complex into a rubber composition for a tire or the like as a vulcanization accelerator (Patent Document 1). However, Patent Document 1 does not relate to a rubber composition for a tire containing a filler. In addition, Patent Document 1 neither discloses nor suggests knowledge for improving fuel consumption performance without sacrificing the wet grip performance of a tire by blending this complex into a rubber composition for a tire containing a filler.